Porous metal complexes that are useful for separating a specific gas from a mixed gas have been developed. For example, Patent Document 1 describes a porous metal complex in which the characteristics of both a gate-type polymer complex exhibiting open-gate type gas adsorption and an type-I complex exhibiting type-I gas adsorption are changed by a switching material. In addition, Patent Document 2 and Patent Document 3 describe a porous metal complex that only selectively adsorbs a specific gas accompanying a change in pore structure or size. Moreover, Patent Document 3 and Non-Patent Document 1 describe a flexible porous metal complex, which changes its structure depending on the type of gas contacted thereby, and a gas separation method using that porous metal complex. The term “porous” described herein refers to a metal complex having a special structure at the molecular level (voids) of a size that can accommodate and release hydrocarbon molecules as target adsorbates. In the case of a metal complex having a flexible structure, the shape and/or size of voids may change due to a structural change caused by pressure or other external stimulus.
However, these documents do not specifically describe the form of a porous metal complex in the case of using in an actual industrial separation process. In addition, although Patent Document 4 describes a molded article composed of a porous metal complex and a binder, the binder is an inorganic compound and there is no description relating to the effects of the binder on the adsorption and desorption behavior of the molded article.